RandFan:
They changed. But they did not change in a way that you suggest. Some changes can happen more quickly than others.
Any physical change which is "transmitted" to the next generation, and is not part of the parents' DNA, is due to a mutation. It makes no difference how much the parents have adapted.
Why is it that even though my wife and I both have blue eyes one of our children has brown eyes?
Recessive genes.
Yes, this is a correct statement. And we know according to Mendelian Genetics that human genetic makeup allows for any group of humans to adapt to changes in environment by changing skin color based upon heritable variation. Just like eye color our offspring can have different skin color based on genes (they don't need to mutate).
I think I'm beginning to understand what you are trying to say. Correct me if I'm wrong, but I think you are saying that the potential for offspring having different characteristics from their parents already exists, even without mutations.
In that case, I agree. The problem, of course, is that the possible differences are minute and of no relevance when discussing races.
[*]Do you know who
Mendelian is?
Sure.
[*]What did his discovery from his experiments with garden peas tell us?
Lots of stuff. Which one are you thinking of?
[*]Did his discovery have anything to do with human skin color?
Indirectly, I would say yes.
[*]Did his experiments suggest that change in attributes like color would require thousands of years?
I don't recall him saying anything on this matter. Is it important?
[*]According to Mendalian, can we predict how many generations it woud take to achieve a change in skin color?
See above.
It is quite simple. According to Mendelian Genetics offspring can adapt to changes in environment because of heritable variation including changes in skin color. Since skin color is more complex than eye color it is a slower process but certainly not as slow as 10's of thousands of years.
I have. I know that variations in skin color can be explained by Mendalian genetics. I know that changes in variations can occur in a short period of time.
Evidence, please!
And not evidence of Mendelev's thoughts, but on how soon existent genes for skin color would manifest a black skin when the ínhabitants just interbreed amon themselves in a sunny environment.
Great straw man. I never claimed that humans mutated to a new species or subspecies. If you would have read the material that I provided you would know that.
You claimed that:
...., if natives of scandinavia were moved to certain parts of Africa and reproduced and their offspring in turn reproduced they would eventully take on the charachterisitcs of native Africans. I think 6 generations is necassary.
Kindly show that this ridiculous assertion has any merit.
BTW, your reasoning is circular.[*]You claim that humans are a sub species.
No I don't.
[*]For proof you site differences in skin color.
No I don't. I simply asked why skin color wouldn't be sufficient to categorize a sub-species.
[*]You claim that skin color would take large periods of time to mutate.
No I don't. I claimed that the seperation of a species into different sub-species would require 1000's of generations.
[*]For proof you state that a sub-species would require large periods of time for to mutate.
Yesish. Not sure what you mean by "proof".
My claims:
- Human can adapt to changes in environment including changes in skin color.
- Changes in skin color are simply a matter of differences in allels which occur to offspring and can be expressed by simple mathmatics.
- These adaptations are the result of heritable variation.
- According to Mendelian Genetics, all humans are capable of producing offspring with different characteristics such as eye color, hair color and skin color.
- Skin color is based upon 3 genes which are responsible for melanin formation in the skin.
- Each gene has 2 alleles: one for making more melanin and one for making less melanin, signified by A or a. Therefore, people can range from AAAAAA (darkest) to aaaaaa (lightest). Intermediate skin tones result from having some A alleles and some a alleles.
- From this palate any skin color can be reproduced from any two humans given enough generations WITHOUT the thousands of years that you talk about.[/list=1]
- Cool. Now please show your claim that this happened in 6 generations.